Two-phase R1234yf flow inside horizontal smooth circular tubes: Heat transfer, pressure drop, and flow pattern

A literature review on the two-phase flow inside plain tubes, especially for refrigerant R1234yf, is conducted in this research. The boiling, condensation, and visualization of low GWP were examined experimentally to measure heat transfer coefficients pressure drop refrigerant, also present a pattern map. measurements carried out smooth circular tubes with internal diameters 8.2 mm mass velocity ranging from 95 410 kg m?2 s?1, vapor qualities 0.12 0.92, saturation temperatures 26.3°C 33.5°C. For range test parameters, patterns observed compared work Wojtan et al. Also, experimental results analyzed evaluate effect quality. Generally, both parameters increase boiling condensing flows. existing models proposed predict coefficient drop. Two correlations, based previous studies, improve accuracy prediction. correlation Dobson was adapted resulted mean absolute error 11.9%. Liu Winterton model modified reduce its 25.6% 13.4%.